Conversion d'unités dans boost.units de angular_velocity en degrés_per_second

Question

Je dois faire une conversion d'une angular_velocity générale en degrés/seconde.

Pour illustrer ce problème, l'exemple boostUnits.cpp:

#include <boost/units/systems/si.hpp> 
#include <boost/units/systems/angle/revolutions.hpp> 
#include <boost/units/systems/angle/degrees.hpp> 
#include <boost/units/conversion.hpp> 
#include <boost/units/pow.hpp> 
#include <iostream> 
#include <iterator> 
#include <algorithm> 

int main() 
{ 
    boost::units::quantity< boost::units::si::angular_velocity> m_speed(
    (30.0*boost::units::si::radians_per_second) 
); 
    std::cout << "m_speed: " << m_speed << std::endl; 

    uint32_t result = static_cast<uint32_t>(
    boost::units::quantity<boost::units::si::angular_velocity,uint32_t>(
     m_speed*boost::units::degree::degrees/boost::units::si::seconds 
    ).value() 
); 
    std::cout << " result: "<< result << std::endl; 

    return(0); 
} 

produit cette sortie du compilateur:

g++ boostUnits.cpp 
/usr/local/include/boost/units/detail/conversion_impl.hpp: In static member function ‘static boost::units::quantity<Unit2, T2> boost::units::conversion_helper<boost::units::quantity<Unit1, T1>, boost::units::quantity<Unit2, T2> >::convert(const boost::units::quantity<Unit1, T1>&) [with Unit1 = boost::units::unit<boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-0x000000002l, 1l> >, boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension, boost::units::static_rational<2l, 1l> >, boost::units::dimensionless_type> >, boost::units::heterogeneous_system<boost::units::heterogeneous_system_impl<boost::units::list<boost::units::heterogeneous_system_dim<boost::units::angle::degree_base_unit, boost::units::static_rational<1l, 1l> >, boost::units::list<boost::units::heterogeneous_system_dim<boost::units::si::second_base_unit, boost::units::static_rational<-0x000000002l, 1l> >, boost::units::list<boost::units::heterogeneous_system_dim<boost::units::angle::radian_base_unit, boost::units::static_rational<1l, 1l> >, boost::units::dimensionless_type> > >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-0x000000002l, 1l> >, boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension, boost::units::static_rational<2l, 1l> >, boost::units::dimensionless_type> >, boost::units::dimensionless_type> >, void>, T1 = double, Unit2 = boost::units::unit<boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-0x000000001l, 1l> >, boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension, boost::units::static_rational<1l, 1l> >, boost::units::dimensionless_type> >, boost::units::homogeneous_system<boost::units::list<boost::units::si::meter_base_unit, boost::units::list<boost::units::scaled_base_unit<boost::units::cgs::gram_base_unit, boost::units::scale<10l, boost::units::static_rational<3l, 1l> > >, boost::units::list<boost::units::si::second_base_unit, boost::units::list<boost::units::si::ampere_base_unit, boost::units::list<boost::units::si::kelvin_base_unit, boost::units::list<boost::units::si::mole_base_unit, boost::units::list<boost::units::si::candela_base_unit, boost::units::list<boost::units::angle::radian_base_unit, boost::units::list<boost::units::angle::steradian_base_unit, boost::units::dimensionless_type> > > > > > > > > >, void>, T2 = unsigned int]’: 
/usr/local/include/boost/units/quantity.hpp:193: instantiated from ‘boost::units::quantity<Unit, Y>::quantity(const boost::units::quantity<Unit2, YY>&, typename boost::disable_if<boost::mpl::and_<typename boost::units::is_implicitly_convertible<Unit2, Unit>::type, boost::units::detail::is_non_narrowing_conversion<YY, Y>, mpl_::bool_<true>, mpl_::bool_<true>, mpl_::bool_<true> >, typename boost::units::detail::disable_if_is_same<Unit, Unit2>::type>::type*) [with Unit2 = boost::units::unit<boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-0x000000002l, 1l> >, boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension, boost::units::static_rational<2l, 1l> >, boost::units::dimensionless_type> >, boost::units::heterogeneous_system<boost::units::heterogeneous_system_impl<boost::units::list<boost::units::heterogeneous_system_dim<boost::units::angle::degree_base_unit, boost::units::static_rational<1l, 1l> >, boost::units::list<boost::units::heterogeneous_system_dim<boost::units::si::second_base_unit, boost::units::static_rational<-0x000000002l, 1l> >, boost::units::list<boost::units::heterogeneous_system_dim<boost::units::angle::radian_base_unit, boost::units::static_rational<1l, 1l> >, boost::units::dimensionless_type> > >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-0x000000002l, 1l> >, boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension, boost::units::static_rational<2l, 1l> >, boost::units::dimensionless_type> >, boost::units::dimensionless_type> >, void>, YY = double, Unit = boost::units::unit<boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-0x000000001l, 1l> >, boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension, boost::units::static_rational<1l, 1l> >, boost::units::dimensionless_type> >, boost::units::homogeneous_system<boost::units::list<boost::units::si::meter_base_unit, boost::units::list<boost::units::scaled_base_unit<boost::units::cgs::gram_base_unit, boost::units::scale<10l, boost::units::static_rational<3l, 1l> > >, boost::units::list<boost::units::si::second_base_unit, boost::units::list<boost::units::si::ampere_base_unit, boost::units::list<boost::units::si::kelvin_base_unit, boost::units::list<boost::units::si::mole_base_unit, boost::units::list<boost::units::si::candela_base_unit, boost::units::list<boost::units::angle::radian_base_unit, boost::units::list<boost::units::angle::steradian_base_unit, boost::units::dimensionless_type> > > > > > > > > >, void>, Y = unsigned int]’ 
boostUnits.cpp:16: instantiated from here 
/usr/local/include/boost/units/detail/conversion_impl.hpp:345: error: no matching function for call to ‘conversion_factor(boost::units::unit<boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-0x000000002l, 1l> >, boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension, boost::units::static_rational<2l, 1l> >, boost::units::dimensionless_type> >, boost::units::heterogeneous_system<boost::units::heterogeneous_system_impl<boost::units::list<boost::units::heterogeneous_system_dim<boost::units::angle::degree_base_unit, boost::units::static_rational<1l, 1l> >, boost::units::list<boost::units::heterogeneous_system_dim<boost::units::si::second_base_unit, boost::units::static_rational<-0x000000002l, 1l> >, boost::units::list<boost::units::heterogeneous_system_dim<boost::units::angle::radian_base_unit, boost::units::static_rational<1l, 1l> >, boost::units::dimensionless_type> > >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-0x000000002l, 1l> >, boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension, boost::units::static_rational<2l, 1l> >, boost::units::dimensionless_type> >, boost::units::dimensionless_type> >, void>&, boost::units::unit<boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-0x000000001l, 1l> >, boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension, boost::units::static_rational<1l, 1l> >, boost::units::dimensionless_type> >, boost::units::homogeneous_system<boost::units::list<boost::units::si::meter_base_unit, boost::units::list<boost::units::scaled_base_unit<boost::units::cgs::gram_base_unit, boost::units::scale<10l, boost::units::static_rational<3l, 1l> > >, boost::units::list<boost::units::si::second_base_unit, boost::units::list<boost::units::si::ampere_base_unit, boost::units::list<boost::units::si::kelvin_base_unit, boost::units::list<boost::units::si::mole_base_unit, boost::units::list<boost::units::si::candela_base_unit, boost::units::list<boost::units::angle::radian_base_unit, boost::units::list<boost::units::angle::steradian_base_unit, boost::units::dimensionless_type> > > > > > > > > >, void>&)’ 

Quelle est la syntaxe pour obtenir la spécification de type souhaité et la conversion ultérieure? Dois-je spécifier une unité degrees_per_second, et si oui, comment?

Documentation: http://www.boost.org/doc/libs/1_37_0/doc/html/boost_units.html

Nous vous remercions d'avance pour votre aide.

Answer 1

Steven Wantabe provided the solution sur la liste de diffusion boost-users.
J'ai implémenté un exemple de travail ci-dessous.

boostUnits.cpp:

#include <boost/units/systems/si.hpp> 
#include <boost/units/systems/angle/revolutions.hpp> 
#include <boost/units/systems/angle/degrees.hpp> 
#include <boost/units/conversion.hpp> 
#include <boost/units/pow.hpp> 
#include <boost/units/io.hpp> 
#include <iostream> 
#include <iterator> 
#include <algorithm> 

    typedef boost::units::divide_typeof_helper< 
     boost::units::degree::plane_angle, 
     boost::units::si::time 
    >::type degrees_per_second; 

int main() 
{ 

    boost::units::quantity< boost::units::si::angular_velocity> m_speed(
    (30.0*boost::units::si::radians_per_second) 
); 

    std::cout << "m_speed rad/sec: " << m_speed << std::endl; 

    std::cout << "m_speed deg/sec: " << 
    static_cast< 
     boost::units::quantity<degrees_per_second> 
    >(m_speed) << 
    std::endl; 

    uint32_t result = static_cast<uint32_t>(
    static_cast< 
     boost::units::quantity<degrees_per_second> 
    >(m_speed).value()); 

    std::cout << "int result: "<< result << std::endl; 

    return(0); 
} 

Terminal Sortie:

g++ boostUnits.cpp 
./a.out 
m_speed rad/sec: 30 s^-1 rad 
m_speed deg/sec: 1718.87 deg s^-1 
int result: 1718 

Answer 2

Vous n'avez pas besoin que beaucoup de code. L'algèbre naturelle peut vous y mener.

#include<boost/units/systems/si/io.hpp> 
#include<boost/units/systems/cgs/io.hpp> 
#include <boost/units/systems/angle/degrees.hpp> 

#include<boost/units/cmath.hpp> 
#include<iostream> 

using std::cout; 
using namespace boost::units; 

int main(){ 

    quantity<si::angular_velocity> m_speed = 30.*si::radian/si::second ; 
    cout 
     << m_speed << '\n' 
     << m_speed/(degree::degree/si::second) << '\n' 
     << quantity<si::dimensionless>(m_speed/(degree::degree/si::second))*(degree::degree/si::second) << '\n' 
     << (quantity<si::dimensionless>(m_speed/(degree::degree/si::second))*(degree::degree/si::second)).value() << '\n' 
     << int((quantity<si::dimensionless>(m_speed/(degree::degree/si::second))*(degree::degree/si::second)).value()) 
    ; 
} 

Sortie:

30 s^-1 rad 
30 deg^-1 rad 
1718.87 deg s^-1 
1718.87 
1718